Saturday 15 November 2008

Variadic via GADT


data Pill a where
Stop :: Pill Integer
O :: Pill (Pill a -> a)

collect :: Integer -> Pill a -> a
collect i Stop = i
collect i O = collect (i+1)

start = collect 0

-- > start Stop
-- 0
-- > start O Stop
-- 1
-- > start O O Stop
-- 2
-- > start O O O Stop
-- 3
-- > start O O O O Stop
-- 4
-- > start O O O O O Stop
-- 5

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